/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    SingleClassifierEnhancer.java
 *    Copyright (C) 2004 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.classifiers;

import weka.classifiers.rules.ZeroR;
import weka.core.Capabilities;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Utils;
import weka.core.Capabilities.Capability;

import java.util.Enumeration;
import java.util.Vector;

/**
 * Abstract utility class for handling settings common to meta classifiers that
 * use a single base learner.
 * 
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision: 5536 $
 */
public abstract class SingleClassifierEnhancer extends Classifier {

	/** for serialization */
	private static final long serialVersionUID = -3665885256363525164L;

	/** The base classifier to use */
	protected Classifier m_Classifier = new ZeroR();

	/**
	 * String describing default classifier.
	 */
	protected String defaultClassifierString() {

		return "weka.classifiers.rules.ZeroR";
	}

	/**
	 * Returns an enumeration describing the available options.
	 * 
	 * @return an enumeration of all the available options.
	 */
	public Enumeration listOptions() {

		Vector newVector = new Vector(3);

		Enumeration enu = super.listOptions();
		while (enu.hasMoreElements()) {
			newVector.addElement(enu.nextElement());
		}

		newVector.addElement(new Option("\tFull name of base classifier.\n"
				+ "\t(default: " + defaultClassifierString() + ")", "W", 1,
				"-W"));

		newVector.addElement(new Option("", "", 0,
				"\nOptions specific to classifier "
						+ m_Classifier.getClass().getName() + ":"));
		enu = ((OptionHandler) m_Classifier).listOptions();
		while (enu.hasMoreElements()) {
			newVector.addElement(enu.nextElement());
		}

		return newVector.elements();
	}

	/**
	 * Parses a given list of options. Valid options are:
	 * <p>
	 * 
	 * -W classname <br>
	 * Specify the full class name of the base learner.
	 * <p>
	 * 
	 * Options after -- are passed to the designated classifier.
	 * <p>
	 * 
	 * @param options
	 *            the list of options as an array of strings
	 * @exception Exception
	 *                if an option is not supported
	 */
	public void setOptions(String[] options) throws Exception {

		super.setOptions(options);

		String classifierName = Utils.getOption('W', options);

		if (classifierName.length() > 0) {

			// This is just to set the classifier in case the option
			// parsing fails.
			setClassifier(Classifier.forName(classifierName, null));
			setClassifier(Classifier.forName(classifierName,
					Utils.partitionOptions(options)));
		} else {

			// This is just to set the classifier in case the option
			// parsing fails.
			setClassifier(Classifier.forName(defaultClassifierString(), null));
			setClassifier(Classifier.forName(defaultClassifierString(),
					Utils.partitionOptions(options)));
		}
	}

	/**
	 * Gets the current settings of the Classifier.
	 * 
	 * @return an array of strings suitable for passing to setOptions
	 */
	public String[] getOptions() {

		String[] classifierOptions = ((OptionHandler) m_Classifier)
				.getOptions();
		int extraOptionsLength = classifierOptions.length;
		if (extraOptionsLength > 0) {
			extraOptionsLength++; // for the double hyphen
		}

		String[] superOptions = super.getOptions();
		String[] options = new String[superOptions.length + extraOptionsLength
				+ 2];

		int current = 0;
		options[current++] = "-W";
		options[current++] = getClassifier().getClass().getName();

		System.arraycopy(superOptions, 0, options, current, superOptions.length);
		current += superOptions.length;

		if (classifierOptions.length > 0) {
			options[current++] = "--";
			System.arraycopy(classifierOptions, 0, options, current,
					classifierOptions.length);
		}

		return options;
	}

	/**
	 * Returns the tip text for this property
	 * 
	 * @return tip text for this property suitable for displaying in the
	 *         explorer/experimenter gui
	 */
	public String classifierTipText() {
		return "The base classifier to be used.";
	}

	/**
	 * Returns default capabilities of the base classifier.
	 * 
	 * @return the capabilities of the base classifier
	 */
	public Capabilities getCapabilities() {
		Capabilities result;

		if (getClassifier() != null) {
			result = getClassifier().getCapabilities();
		} else {
			result = new Capabilities(this);
			result.disableAll();
		}

		// set dependencies
		for (Capability cap : Capability.values())
			result.enableDependency(cap);

		result.setOwner(this);

		return result;
	}

	/**
	 * Set the base learner.
	 * 
	 * @param newClassifier
	 *            the classifier to use.
	 */
	public void setClassifier(Classifier newClassifier) {

		m_Classifier = newClassifier;
	}

	/**
	 * Get the classifier used as the base learner.
	 * 
	 * @return the classifier used as the classifier
	 */
	public Classifier getClassifier() {

		return m_Classifier;
	}

	/**
	 * Gets the classifier specification string, which contains the class name
	 * of the classifier and any options to the classifier
	 * 
	 * @return the classifier string
	 */
	protected String getClassifierSpec() {

		Classifier c = getClassifier();
		return c.getClass().getName() + " "
				+ Utils.joinOptions(((OptionHandler) c).getOptions());
	}
}
